Abstract 18472: Enhancing the Therapeutic Potential of Induced Pluripotent Stem Cell Derived Cardiomyocytes Through Targeting the Hippo Signalling Pathway
Cell based therapy using stem cell derived cardiomyocytes, has emerged as a potential therapeutic approach for cardiac diseases such as myocardial infarction and heart failure. Induced pluripotent stem cells (iPSC) could be an ideal source of cardiomyocytes (iPS-CM). However, challenges facing this approach include the high number of viable cells needed to survive in pathological conditions. The Hippo signalling pathway is a key pathway involved in regulating cardiomyocyte proliferation and survival in both embryonic and adult hearts. In this study, we target the Hippo pathway to enhance the therapeutic potential of iPS-CM.Skin fibroblasts were reprogrammed to iPSC and then differentiated to cardiomyocytes. The Hippo pathway was modified by genetic ablation of Mst1, a major upstream regulator of the Hippo pathway, or by overexpressing YAP, the main downstream effector of the pathway. We found that genetic ablation of Mst1 leads to significantly increased reprogramming efficiency by 43.8±2.4%. iPSC lacking MST1 displayed increase proliferation (12±1.5% P<0.001), survival and viability (20±4.3% P<0.001) in both normal and hypoxic conditions compared to controls. In addition, overexpression of wild type and the constitutively active form of YAP (S127A) increased cell proliferation in iPS-CM compared to control iPS-CM as shown with an EdU assay (+20.8±1.6% P<0.01) and Ki67 staining (4.9±0.9% P<0.001). Overexpression of YAP leads to up regulation of genes associated with inhibition of apoptosis and promotion of cell proliferation. Preliminary studies show that mouse iPS-CM with overexpression of YAP (S127A) are retained in the myocardium following intracardiac injection and does not cause any adverse effects as confirmed by histological, echocardiography and electrocardiogram analyses. In conclusion, targeting the Hippo pathway in iPSC and iPS-CM significantly increases proliferation and survival in both normal and hypoxic conditions. Therefore, modulation of the Hippo pathway could become a new strategy to enhance the therapeutic potential of iPS-CM.
Author Disclosures: A.C. Robertson: None. T. Mohammed: None. M. Zi: None. S. Prehar: None. N. Stafford: None. E.J. Cartwright: None. D. Oceandy: None.
- © 2016 by American Heart Association, Inc.